<p>
  Return on Equity(ROE) is defined as the ratio of net income over shareholders equity,
  where shareholders’ equity is the difference between a company's total assets and total liabilities. Shareholders' equity is often referred to as the book value of the company.
  ROE is a measure of how efficiently a company uses its assets to produce earnings. It can explain many anomalies related to earnings and profitability. This algorithm will build a long-short portfolio with ROE factor.
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